<template>
  <div>
    <label for="all">全选:</label>
    <input type="checkbox" id="all" v-model="all"/>
    <ul>
      <li v-for="item in arr" :key="item.name">
        <input type="checkbox" v-model="item.c"/>
        <span>{{item.name}}</span>
      </li>
    </ul>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [
        { name: '猪八戒', c: false },
        { name: '孙悟空', c: false },
        { name: '唐僧', c: false },
        { name: '白龙马', c: false }
      ]
    }
  },
  computed: {
    all: {
      get(){
        // 点击小框，控制大框
        return this.arr.every(item => item.c)
      },
      set(val){
        this.arr.forEach(item => item.c = val)
      }
    }
  }
}
</script>
